w! Appara- There shall be placed upon this switchnecuons.Con- board, in addition to all the dynamo regulating apparatus, such switches, cut-outs and other appliances as are necessary for the proper and convenient manipulation of the circuits, such appliances to be named by each bidder in his proposal.

For the two-wire, direct-current system the appliances and connections shall be such as will permit any dynamo to be added to or taken from parallel circuit without in any manner affecting the operation of the dynamos remaining in circuit, or the candle-power and steadiness of the lamps.

For the three-wire, direct-current system the appliances and connections shall be such as will permit any dynamo on either side to be added to or taken from parallel circuit without in any manner affecting the operation of the dynamos remaining in circuit on that side, or the candle-power and steadiness of the lamps; and a breakdown switch for connecting the two outside wires in case it shall be • come necessary or desirable to operate on the two-wire system.

For the alternating-current system the appliances and connections shall be such as will permit the operation of any dynamo on any circuit or number of circuits, and the cutting in or out of any dynamo or circuit with certainty and rapidity, without in any manner affecting the operation of other dynamos or circuits (and such that it will be possible to connect two dynamos together by an arrangement of switches or combination of circuits.) (For switchboard connections see sees. 30 and 31, pp. 55 and 56.

Each dynamo shall be provided with a regulator which shall automatically make the proper adjustments for all changes of load from no load to full load, the adjustments to be made in such a way as not to endanger any part of the dynamo, appliances or lamps, nor to cause any perceptible change in the balance remaining in operation; shall be of the latest and most efficient pattern; mounted on a base provided with an adjustable belt-tightener, so that the belt may be tightened while in operation; capable of operating under full